Studies have indicated that restriction of caloric intake by food deprivation slows down certain undesirable cellular processes in laboratory animals, many associated with aging and age-related diseases.
In particular, caloric restriction has been shown to consistently extend the life span, delay onset and slow tumor progression, and retard physiologic aging in many systems. Indeed, research spanning more than sixty years has shown that caloric restriction is a nutritional intervention that consistently extends longevity in animals. See Weindruch and Walford, “The Retardation of Aging and Disease by Dietary Restriction,” Springfield, Ill.: Charles C. Thomas (1988); Yu, “Modulation of Aging Processes by Dietary Restriction,” Boca Raton: CRC Press (1994); and Fishbein, “Biological Effects of Dietary Restriction,” Springer, N.Y. (1991). These effects of caloric restriction on life span and tumorigenesis have been reported numerous times since the early studies of McKay. See McKay et al., “The Effect of Retarded Growth Upon the Length of Lifespan and Upon Ultimate Body Size,” J. Nutr., Vol. 10, pp. 63-79 (1935). Indeed, over the past two decades, a resurgence of interest in caloric restriction in gerontology has led to the general acceptance that this dietary manipulation slows physiologic aging in many systems. See Weindruch and Walford, “The Retardation of Aging and Disease by Dietary Restriction,” Springfield, Ill.: Charles C. Thomas (1988); Yu, “Modulation of Aging Processes by Dietary Restriction,” Boca Raton: CRC Press (1994); and Fishbein, “Biological Effects of Dietary Restriction,” Springer, N.Y. (1991).
Reductions in fasting glucose and insulin levels are readily measured biomarkers of caloric restriction. Calorically restricted rodents exhibit lower fasting glucose and insulin levels, and the peak glucose and insulin levels reached during a glucose challenge are reduced in those on caloric restriction. See Kalant et al., “Effect of Diet Restriction on Glucose Metabolism and Insulin Responsiveness and Aging Rats,” Mech. Aging Dev., Vol. 46, pp. 89-104 (1988). It is also known that hyperinsulinemia is a risk factor associated with several such disease processes, including heart disease and diabetes (Balkau and Eschwege, Diabetes Obes. Metab. 1 (Suppl. 1): S23-31, 1999). Reduced insulin levels and body temperature are two of the most reliable indicators of this altered metabolic profile (Masoro et al., J. Gerontol. Biol. Sci. 47:B202-B208, 1992); Koizumi et al., J. Nutr. 117: 361-367, 1987; Lane et al., Proc. Nat. Acad. Sci. 93:4154-4164, 1996).
Components such as 2-deoxy-D-glucose have been described which block or inhibit certain aspects of carbohydrate metabolism and may therefore mimic the effects of caloric restriction (Rezek et al., J. Nutr. 106:143-157, 1972; U.S. Patent Application Publication No. 2002/0035071). These components exert a number of physiological effects, including reduction of body weight, decrease in plasma insulin levels, reduction of body temperature, retardation of tumor formation and growth, and elevation of circulating glucocorticoid hormone concentrations. (For a review see Roth et al., Ann. NY Acad. Sci. 928:305-315, 2001). These effects result from inhibition of carbohydrate metabolism.
However, the commercial utility of such components has been limited, particularly as practical applications had yet been identified. The present inventors herein provide compositions which may be commercially utilized, and further provide processes for preparation of such compositions. In particular, it has been found that the components herein may be processed from plant matter, or otherwise provided, and then subjected to traditional pet food processing (such as, for example, extrusion or other such vigorous methods) without compromising the integrity of the component.